Hi Abhinav,
Sorry for the delay in reviewing this, Easter break happened in between.
On Fri, Apr 08, 2022 at 05:53:54PM -0700, Abhinav Kumar wrote:
> For some vendor driver implementations, display hardware can
> be shared between the encoder used for writeback and the physical
> display.
>
> In addition resources such as clocks and interrupts can
> also be shared between writeback and the real encoder.
>
> To accommodate such vendor drivers and hardware, allow
> real encoder to be passed for drm_writeback_connector.
>
> For existing clients, drm_writeback_connector_init() will use
> an internal_encoder under the hood and hence no changes will
> be needed.
>
> changes in v7:
> - move this change before the vc4 change in the series
> to minimize the changes to vendor drivers in drm core
> changes
>
> Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_writeback.c | 18 ++++++++++++------
> drivers/gpu/drm/vc4/vc4_txp.c | 4 ++--
> include/drm/drm_writeback.h | 22 ++++++++++++++++++++--
> 3 files changed, 34 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
> index 92658ad..0538674 100644
> --- a/drivers/gpu/drm/drm_writeback.c
> +++ b/drivers/gpu/drm/drm_writeback.c
> @@ -180,21 +180,21 @@ int drm_writeback_connector_init(struct drm_device *dev,
> {
> int ret = 0;
>
> - drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);
> + drm_encoder_helper_add(&wb_connector->internal_encoder, enc_helper_funcs);
>
> - wb_connector->encoder.possible_crtcs = possible_crtcs;
> + wb_connector->internal_encoder.possible_crtcs = possible_crtcs;
>
> - ret = drm_encoder_init(dev, &wb_connector->encoder,
> + ret = drm_encoder_init(dev, &wb_connector->internal_encoder,
> &drm_writeback_encoder_funcs,
> DRM_MODE_ENCODER_VIRTUAL, NULL);
> if (ret)
> return ret;
>
> - ret = drm_writeback_connector_init_with_encoder(dev, wb_connector, &wb_connector->encoder,
> - con_funcs, formats, n_formats);
> + ret = drm_writeback_connector_init_with_encoder(dev, wb_connector,
> + &wb_connector->internal_encoder, con_funcs, formats, n_formats);
>
> if (ret)
> - drm_encoder_cleanup(&wb_connector->encoder);
> + drm_encoder_cleanup(&wb_connector->internal_encoder);
>
> return ret;
> }
> @@ -239,6 +239,12 @@ int drm_writeback_connector_init_with_encoder(struct drm_device *dev,
> struct drm_mode_config *config = &dev->mode_config;
> int ret = create_writeback_properties(dev);
>
> + /*
> + * Assign the encoder passed to this API to the wb_connector's encoder.
> + * For drm_writeback_connector_init(), this shall be the internal_encoder
> + */
> + wb_connector->encoder = enc;
> +
> if (ret != 0)
> return ret;
>
> diff --git a/drivers/gpu/drm/vc4/vc4_txp.c b/drivers/gpu/drm/vc4/vc4_txp.c
> index 3447eb6..7e063a9 100644
> --- a/drivers/gpu/drm/vc4/vc4_txp.c
> +++ b/drivers/gpu/drm/vc4/vc4_txp.c
> @@ -159,7 +159,7 @@ struct vc4_txp {
>
> static inline struct vc4_txp *encoder_to_vc4_txp(struct drm_encoder *encoder)
> {
> - return container_of(encoder, struct vc4_txp, connector.encoder);
> + return container_of(encoder, struct vc4_txp, connector.internal_encoder);
This doesn't feel right. First, vc4_txp should not be aware of the existance of
internal_encoder, that is only for the use of drm_writeback_connector when someone
doesn't pass on an encoder. Second, how do we know someone didn't actually use the
'encoder' pointer from drm_writeback_connector? I think we should be consistent and
only use encoder member.
Best regards,
Liviu
> }
>
> static inline struct vc4_txp *connector_to_vc4_txp(struct drm_connector *conn)
> @@ -507,7 +507,7 @@ static int vc4_txp_bind(struct device *dev, struct device *master, void *data)
> if (ret)
> return ret;
>
> - encoder = &txp->connector.encoder;
> + encoder = txp->connector.encoder;
> encoder->possible_crtcs = drm_crtc_mask(crtc);
>
> ret = devm_request_irq(dev, irq, vc4_txp_interrupt, 0,
> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
> index bb306fa..3fbae9d 100644
> --- a/include/drm/drm_writeback.h
> +++ b/include/drm/drm_writeback.h
> @@ -25,13 +25,31 @@ struct drm_writeback_connector {
> struct drm_connector base;
>
> /**
> - * @encoder: Internal encoder used by the connector to fulfill
> + * @encoder: handle to drm_encoder used by the connector to fulfill
> * the DRM framework requirements. The users of the
> * @drm_writeback_connector control the behaviour of the @encoder
> * by passing the @enc_funcs parameter to drm_writeback_connector_init()
> * function.
> + *
> + * For some vendor drivers, the hardware resources are shared between
> + * writeback encoder and rest of the display pipeline.
> + * To accommodate such cases, encoder is a handle to the real encoder
> + * hardware.
> + *
> + * For current existing writeback users, this shall continue to be the
> + * embedded encoder for the writeback connector.
> + */
> + struct drm_encoder *encoder;
> +
> + /**
> + * @internal_encoder: internal encoder used by writeback when
> + * drm_writeback_connector_init() is used.
> + * @encoder will be assigned to this for those cases
> + *
> + * This will be unused when drm_writeback_connector_init_with_encoder()
> + * is used.
> */
> - struct drm_encoder encoder;
> + struct drm_encoder internal_encoder;
>
> /**
> * @pixel_formats_blob_ptr:
> --
> 2.7.4
>
--
====================
| I would like to |
| fix the world, |
| but they're not |
| giving me the |
\ source code! /
---------------
¯\_(ツ)_/¯
